There is still much debate on this topic. Depends who you ask. I haven’t done a side by side tasting experiment to come to any firm conclusions, but I would suggest that anyone interested should do so. I hypothesize that pellets might be superior to whole hops. But that’s just a guess; I don’t really know for sure.
And its also very dependdent on who makes the pellets and how they’re made. Not all pellets are equal. I have found pellets superior to whole hops for many reasons, but I know how the pellets I get are made.
That could be because, typically, you get about 10% better utilization out of pellets. Even if what you suspect is true, the advantages of using pellets still outweigh any negatives. A negative like being slightly harsher can easily be remedied.
Once I went to stainless mesh canisters for pellet hops, it changed my preference to pellets. I’m not terribly concerned with how the hops are pelletized, as long as the results are good. My LHBS sells Yakima Chief, mostly, so maybe I’ve just been lucky with what I’ve bought from it…
In my experience, dry hopping was the place where I could tell the difference between pellets and whole hops. Specifically, getting really bad oxidation problems using whole hops to dry hop American IPAs. I like whole hops when they’re fresh otherwise, but for European varieties that seems to be rare.
Brulosophy did a side by side comparison of pellet vs whole cone hops. Out of 21 tasters in a triangle test 12 of them were able to pick out the unique sample. They then took those 12 and asked them to take a preference survey. Three said they prefer the sample made with whole cone hops. and three said they preferred the one made with pellet hops. The remaining 6 had no preference.
After all of that however they author had this to say in his conclusions:
One unavoidable caveat to this xBmt is that, despite the hops being of the same variety and crop year, as well as from the same source, there’s no way to be certain they came from the same farm or processor. As such, it’s impossible to say with confidence that the differences perceived by tasters in this xBmt were due only to the form the hops were in, as it could be a function of something like growing conditions, processing, etc.